Answer: I had that before it's a riddle. Here lemme find it and give you the answer.
Explanation:
1.H
2.E
3.C
4.O
5.U
6.L
7.D
8.U
9.T
10.P
11. N
12.T
13.I
14.T
15.D
16.O
17.N
18.W
Answer:
(B) Her results are both precise and accurate.
Explanation:
In Chemistry, Accuracy refers to how close a measurement is to it's standard value or known value. On the other hand, Precision means how close two measurement are to each other regardless whether the results are accurate or not.
In the above question, all the above results are very close to each other. That's why the results are Precise to each other. All the results are close enough to the actual value of the experiment. That's why the result are also accurate.
Answer:
Yes, it is.
Explanation:
A buffer is a solution in which a weak acid is in equilibrium with its conjugate base, or a weak base is in equilibrium with its conjugate acid. Because of the equilibrium, when an acid or a base is added to it, the pH remains almost unaltered.
But the buffer has a limit, generally, it works well in the range of pKa - 1 to pKa +1. The pKa value indicates the force of the acid, and it's calculated by -logKa, where Ka is the equilibrium constant of the acid. The pKa value of citric acid is 6.86, does a buffer of it can function well at pH 7.
The successive deprotonations of the acid increase the "-" charge density on the resulting anion, in this case, the carboxylate groups. This is unfavorable electrostatic repulsions between the anions which reduces the likelihood that a proton would dissociate. So, it's more favorable for the proton to remain bound to reduce unfavorable charge repulsion. Because of that, the equilibrium can be achieved.
Answer:
0.4694 moles of CrCl₃
Explanation:
The balanced equation is:
Cr₂O₃(s) + 3CCl₄(l) → 2CrCl₃(s) + 3COCl₂(aq)
The stoichiometry of the equation is how much moles of the substances must react to form the products, and it's represented by the coefficients of the balanced equation. So, 1 mol of Cr₂O₃ must react with 3 moles of CCl₄ to form 2 moles of CrCl₃ and 3 moles of COCl₂.
The stoichiometry calculus must be on a moles basis. The compounds of interest are Cr₂O₃ and CrCl₃. The molar masses of the elements are:
MCr = 52 g/mol
MCl = 35.5 g/mol
MO = 16 g/mol
So, the molar mass of the Cr₂O₃ is = 2x52 + 3x35.5 = 210.5 g/mol.
The number of moles is the mass divided by the molar mass, so:
n = 49.4/210.5 = 0.2347 mol of Cr₂O₃.
For the stoichiometry:
1 mol of Cr₂O₃ ------------------- 2 moles of CrCl₃
0.2347 mol of Cr₂O₃----------- x
By a simple direct three rule:
x = 0.4694 moles of CrCl₃
173.99cm multiply 68.5 x 2.54 always use that number when converting inches to cm
